Interlaminar toughening in carbon fiber/epoxy composites interleaved with CNT-decorated polycaprolactone nanofibers

A major problem with carbon fiber/epoxy (CF/EP) composites is their weakness to resist interlaminar delamination originating from the brittle epoxy matrix. Interleaving has been long studied as a solution. In this work, carbon nanotubes (CNTs) were uniformly decorated on electrospun polycaprolactone (PCL) nanofibers by ultrasonication to form flexible interleaves for CF/EP laminates. Upon epoxy curing, PCL nanofibers were phase separated from epoxy, and CNTs could be uniformly distributed within the matrix. Results obtained showed that modes I and II interlaminar fracture energies of CF/EP laminates interleaved with CNT-decorated PCL nanofibers were enhanced by 68% and 44%, respectively. Synchronous improvement of 7.5% on the interlaminar shear strength of CF/EP laminates were also achieved. Moreover, the glass transition temperature of the interleaved laminates was maintained as that of epoxy because of the introduction of the CNTs.

Automated summary

In this study, flexible interleaves for CF/EP laminates were successfully created by uniformly decorating carbon nanotubes (CNTs) on electrospun polycaprolactone (PCL) nanofibers through ultrasonication. The enhanced interlaminar fracture energies and interlaminar shear strength of the laminates were achieved by introducing CNT-decorated PCL nanofibers, while maintaining the glass transition temperature as that of epoxy.